Machine guard

ABSTRACT

A machine guard for protecting the machine operator and others comprising a cage-like hood adapted to at least partially cover the machine when in use and capable of being swung away from the machine to a retracted position. Means are provided to cut off power to the machine immediately upon initial retraction of the hood.

nited States Patent 1191 Scott [4 1 Jan. 8, 19741 MACHINE GUARD2,555,346 6/1951 Larsen 192 133 [76] Inventor: Robn E. Scott, 1471 ClubDr. 2,557,300 6/1951 Lowry 74/612 X Bloomfield Hills, Mich. 48013Primary Eraminer-Charles J. Myhre [22] Flled: May 1972 Assistant E.\'aminerF. D. Shoemaker 211 App] 25 4 Atrorney-Wi1liam H. Griffith 52US. (:1. 74/ 12, 192/133 [57] ABSTRACT ii ntidCLfus. 2/1022 A machineguard for protecting the machine Operator 0 earc and others comprising acage-like hood adapted to at least partially cover the machine when inuse and capable of being swung away from the machine to a re- [56]References .Clted tracted position. Means are provided to cut off powerUNITED STATES PATENTS to the machine immediately upon initial retractionof 2,913,926 [1/1959 Hammond 74/612 the hOOd. 2,307,524 1/1943 Malcom74/612 2,491,035 12/1949 Deacon 192/133 6 Claims, 4 Drawing Figures f 'JL' 1/ 26 a l f 42 S 2 4O 32 l4 3o 34 MACHINE GUARD BACKGROUND ANDSUMMARY OF THE INVENTION Government safety standards now require specialguards on certain machines and in particular those having reciprocatingactions. Until recently, guards were not always used. Those employedwere difficult to handle and usually took up too much space. It is aprincipal object of this invention to provide a machine guard which isof an improved construction and which meets government standards now inforce.

Another object of the invention is to provide a machine guard which willtake up a minimum of floor space and offer the least inconvenience tothe operator and to setup personnel.

Another object'is to provide a machine guard having means for preventingmachine operation when the guard is removed or retracted.

Another object is to provide a machine guard which is portable and whichwill not interfere with the operation of the machine. 3

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawing wherein:

FIG. I is a perspective view of machine guard apparatus set up adjacentto a machine and shown in retracted position.

FIG. 2 is a perspective view similar to FIG. 1 but showing the machineguard in its operative position of use.

' FIG. 3 is an enlarged fragmentary perspective view of a portion ofFIG. I

FIG. 4 is a diagrammatic view showing the machine motor and the safetyswitch associated therewith.

Referring now more particularly to the drawing, the machine guardapparatus is shown in association with a machine M which may be of anyparticular type such as a fourslide machine, for example.

The apparatus 10 includes a guard 12 which is in the form of a cage orbox-like hood and which is adapted to fit over and cover the machinewhen the machine is in use, as shown in FIG. 2. The apparatus alsoincludes a portable support or stand 14 upon which the guard is mounted.

The guard or hood 12 has a top wall 16, side walls 18 and end walls 20and 22. These walls may be of any suitable construction but are hereshown as being of open grid construction which may be formed, forexample, from expanded metal to enable the machine operator to view theoperation of the machine through the guard 12. The walls of the guardare joined along their edges by the metal framing 23, and the bottom ofthe guard is open so that it may fit over and partially cover the sidesof the machine.

An opening 24 is formed in the end wall 22 to provide clearance for thestrip of material 26 being fed into the machine from the supply reel 28,and is large The stand 14 comprises a pair of identical, laterallyspaced uprights 30 which may include the vertical legs 32 and thesupporting bases 34. A horizontal pivot shaft 36 connects the upper endsof the legs 32.

The guard 12 has plates 38 on the side walls 18 formed with openings topivotally receive the shaft 36, whereby-the guard 12 is hinged forpivotal movement about the shaft 36 between the FIG. I and FIG. 2positions.

The uprights 30 are provided with rest pads or stops 44 and 46. Whilethe exact form of construction may vary, in this instance the stops 44and 46 are carried by arms 40 and 42. Arms 40 are shown as being securedat their lower ends to the legs and inclined upwardly and forwardlyhaving the stops 44 on their upper ends. Arms 42 are shown as beingsecured to legs 32 at their lower ends and inclined upwardly andrearwardly, having the stops 46 on their upper ends. The stops 44 of thetwo uprights 30 are disposed in a common horizontal plane, as are stops46.

When the guard 12 is in its operative position, or position of use,shown in FIG. 2, it extends horizontally from the pivot shaft 36 withits bottom frame bars 48 respectively resting upon and supported by thestops 42. When the guard is raised to the generally upright position ofFIG. 1 in which it is retracted from the machine, its frame bars 50 restupon and are supported by the respective stops 46. As the guard israised from the FIG. 2 to the FIG. 1 position, its center of gravitypasses over the pivot shaft 36 so that it will be in a stable overcentercondition when resting upon the stops 46. In the raised orretractedposition of FIG. 1, the guard uncovers and fully exposes the machine Mso that it can be attended to without interference.

A coil spring 52 encircles pivot shaft 36 and serves as acounterbalancing means for the guard. One end of the spring is securedtoa block 54 rigidly mounted on the pivot shaftQThe other end 56 of thespring is rigidly secured to a plate 38 on the guard. The coil spring issuch that it winds up or is placed in increasing tension when the guardis loweredto the FIG. 2 position, and unwinds when it is raised to theFIG. 1 position. Thus 7 the coil spring 52 serves as a counterbalanceand makes it easier to manually lift the guard to the FIG. 1 position.It also remains under sufficient tension in the FIG. 1 position tosupply a resilient force tending to hold the guard seated in theover-center position of FIG. I at rest upon the stops 46.

While stops 40 and 46 are preferably provided on both uprights 30, suchstops 40 and 46 may if desired be provided on one only of the uprights30. i

The machine M has an electric motor 60 for driving the various slidesand components of the machine. Lines L1, L2 and L3 supply electricalpower to the motor. A switch S is provided for opening and closing theelectrical circuit. Switch S is normally open as shown in FIG. 4.

Switch S is carried by one of the stops 44 as shown in FIG. 3, and itsactuating button 62 extends above the level of the stop in a position tobe engaged and depressed by the frame bar 48 of the guard when the guardis lowered to the operative position of FIG. 2 and the frame bar restsupon stop 44.

When thus depressed, the button 62 closes switch S to close the circuitto motor 60 so that it may operate the machine. However, upon initialraising of the guard 12 from the FIG. 2 position, button 62 is releasedand the switch S returns to its normally open position cutting off powerto the motor 60 and rendering the motor 60 and the machine partsinoperative until the guard is once again returned to the FIG. 2position.

The apparatus of my invention is portable, takes up a minimum of floorspace, and fully protects the operator and others near the machine. Theguard is easily lifted to an out-of-the-way position to allow access tothe machine.

What I claim as my invention is:

1. Apparatus for guarding a machine comprising a support adapted to bepositioned adjacent to a machine, a guard adapted to at least partiallycover the machine when in operative position with respect thereto, meanscomprising a hinge connection mounting said guard on said support forswinging movement from said operative position to a retracted position,said guard when in said operative position extending generallyhorizontally and when in said retracted position being raised so as toextend generally upward from said hinge connection, stops for supportingsaid guard in said operative and retracted positions, said guard when insaid retracted position resting on one of said stops in a stable,over-center position, and counterbalancing means urging said guardtoward said raised retracted position.

2. The apparatus defined in claim 1, wherein said counterbalancing meanscomprises a coil spring associated with said hinge connection.

3. The apparatus defined in claim 2, wherein said guard has an openingof an extent sufficient to clear an elongated member fed into themachine in said operative and retracted positions and in allintermediate positions.

4. The apparatus defined in claim 3, including a i switch forcontrolling electrical energy to the machine being guarded, said switchbeing normally open to interrupt the flow of electrical energy and beingmounted on the stop which supports said guard in its operative position,and means on said guard for engaging and closing said switch when saidguard is in its operative position.

5. Apparatus for guarding a machine comprising a support adapted to bepositioned adjacent to a ma-' .for supporting said guard in saidretracted position, and

counterbalancing means urging said guard toward its retracted position.

6. The apparatus defined in claim 5, including switch means forcontrolling electrical energy to the machine being guarded, and meansfor closing said switch means in response to movement of said guard tosaid operative position and for opening said switch means when saidguard is moved away from said operative position.

1. Apparatus for guarding a machine comprising a support adapted to bepositioned adjacent to a machine, a guard adapted to at least partiallYcover the machine when in operative position with respect thereto, meanscomprising a hinge connection mounting said guard on said support forswinging movement from said operative position to a retracted position,said guard when in said operative position extending generallyhorizontally and when in said retracted position being raised so as toextend generally upward from said hinge connection, stops for supportingsaid guard in said operative and retracted positions, said guard when insaid retracted position resting on one of said stops in a stable,over-center position, and counterbalancing means urging said guardtoward said raised retracted position.
 2. The apparatus defined in claim1, wherein said counterbalancing means comprises a coil springassociated with said hinge connection.
 3. The apparatus defined in claim2, wherein said guard has an opening of an extent sufficient to clear anelongated member fed into the machine in said operative and retractedpositions and in all intermediate positions.
 4. The apparatus defined inclaim 3, including a switch for controlling electrical energy to themachine being guarded, said switch being normally open to interrupt theflow of electrical energy and being mounted on the stop which supportssaid guard in its operative position, and means on said guard forengaging and closing said switch when said guard is in its operativeposition.
 5. Apparatus for guarding a machine comprising a supportadapted to be positioned adjacent to a machine, a guard adapted to atleast partially cover the machine when in operative position withrespect thereto, pivot means mounting said guard on said support forpivotal movement from an operative position in which the center ofgravity of said guard is at one side of the axis of said pivot means toa retracted position in which the center of gravity of said guard is atthe opposite side of said axis of said pivot means such that said guardis in a stable, over-center condition, a stop for supporting said guardin said retracted position, and counterbalancing means urging said guardtoward its retracted position.
 6. The apparatus defined in claim 5,including switch means for controlling electrical energy to the machinebeing guarded, and means for closing said switch means in response tomovement of said guard to said operative position and for opening saidswitch means when said guard is moved away from said operative position.